Metal cations intercalated titanate nanotubes as catalysts for α,β unsaturated esters production Original Research Article

Characterization and catalytic performances of cations (M = Ce4+, La3+, Co2+, Cu2+ or Na+) intercalated titanate nanotubes (MTNT) were performed for α,β unsaturated esters production. Structural properties of the solids were evaluated by transmission electron microscopy (TEM) analysis and X-ray diffraction (XRD), and Raman spectroscopy measurements whereas textural properties were obtained through nitrogen adsorption–desorption isotherms. The transition metals were intercalated in titanate nanotubes by ionic exchange reaction where the Na+ cations were substituted by Ce4+, La3+, Co2+ and Cu2+ ones. Also, the structural characterizations revealed that the ion-exchange processes can favour the formation of nanosized oxides on the TNT surfaces, in some cases. Textural analysis showed high surface area, pore volume and diameters, but a superior catalytic activity and recyclability was only observed for CeTNT and LaTNT catalysts. The improved performance of CeTNT was believed to be related to the presence of Ce4+ cations in the interlamellar region and CeO2 nanosized particles on TNT surface as well.